Provided is an information processing system capable of controlling a user s own name disclosed to other user in accordance with the relationship with the other user. A user management server stores, for each of a plurality of users, an identification name adapted to identify the user in association with a restricted disclosure name registered by the user and information identifying a user entitled to disclosure to whom the disclosure of the restricted disclosure name is permitted. The user management server receives a request for acquisition of name information of a requested user including information identifying a requesting user from a client device. The user management server transmits the restricted disclosure name of the requested user as a reply to the acquisition request if the requesting user is registered as a user entitled to disclosure of the requested user. If not, the user management server transmits the identification name of the requested user. The client device shows the transmitted name information of the requested user on a display screen.